Impulse sender



Nov; 2 7, 1945. H. T. STENHAMMER IMPULSE SENDER Filed May 19, 1944 IN VEN TOR. Harold If SZenkammer- 2%ZOXM Patented Nov. 27, 1945 IMPULSE SENDER Harold T. Stenhammer, New York, N. Y., assignor to Control Instrument Company, Inc., Brooklyn, N. Y.,-a corporation of New York Application May 19, 1944, Serial No. 536,300

8 Claims.

This invention relates to improvements in impulse senders and has particular reference to a device such as used for the transmission of im pulses employed to directively control switches of an automatic telephone system.

Devices of this type have been heretofore suggested in which provision has been made to reduce the amount of clicking noise incident to the passage of an operating pawl over the teeth of a ratchet and into the notches between such teeth. A device of this kind involves the use of a spring mounted upon the pawl and s0 arranged thereon that it will cushion and limit the movement of the pawl int the notches of a ratchet so that the pawl will be prevented from striking the bottom of a notch each time it rides over and beyond the adjacent tooth. While said device operates satisfactorily, it is comparatively expensive to manufacture because of the special construction of the pawl and the mounting of the cushioning spring thereon.

The present invention is accordingly designed to provide an improved arrangement of cushioning means which is of simple, practical, and economical construction and which will effectively reduce the amount of noise inherent in senders that lack a silencing feature. In carrying out the invention, the cushioning means thereof is mounted independently of the pawl and is engageable therewith only during the initial movement of the finger dial.

The inventive idea involved is capable of receiving a variety of mechanical expressions one of which, for purposes of illustration, is shown in the accompanying drawing; but it is to be expressly understood that said drawing is utilized only to facilitate the description of the invention as a whole and not define the limits thereof, reference being had to the appended claims for this purpose.

In the drawing:

Fig. l is a front elevation of an impulse sender constructed in accordance with the invention, the finger dial being removed so as to expose the pawl and ratchet mechanism.

Fig. 2 is an enlarged fragmentary plan view of the pawl and ratchet mechanism showing the same in the reverse position, and illustrating the position of the parts during and at the end of the initial rotation of the finger dial.

Fig. 3 is a view similar to Fig. 2 showing the position of the parts after the release of the dial and at the beginning of the driving operation of the pawl, and

Fig. 4 is a perspective view of the cushioning tion.

spring employed in connection with the inven- As disclosed herein, the device of the present invention is applicable to various types of impulse senders, one of which is illustrated in the Obergfell Patent No. 1,642,822, dated September 20, 1927. In said patent, there is provided a finger dial which is variably rotatable in accordance with the difierent numbers of impulses to be transmitted, said dial being attached to a member or plate carrying a pivotally mounted pawl. Cooperating with said pawl is a ratchet having a number of teeth spaced apart by intervening notches. The ratchet is associated with a gear wheel that drives an impulse sending mechanism. When the finger dial is rotated away from its normal position, said plate is also rotated and carries the pawl therewith so that it will freely ride over the teeth and notches of said ratchet, the number of teeth over which the pawlis rotated being dependent upon the number of impulses to be transmitted. As is customary with devices of this kind, the arrangement and construction of the pawl and ratchet are such that when the finger, inserted into the selected dial opening, strikes against the usual finger stop, the tooth-engaging face of the pawl will have received an overthrow movement which causes it to pass slightly beyond the pawl-engaging face of a tooth on said ratchet so that as said pawl starts to move into the notch adjacent said tooth, there will be a slight gap between said faces sufficient t insure engagement between the pawl and the desired tooth, which gap is closed by an initial movement of the paWl relative to the ratchet as the finger is withdrawn from the dial and said pawl starts its driving stroke to operate the impulse sending mechanism. As will be apparent from the following description, this relative movement between the pawl and ratchet as the dial starts its return movement is utilized to free the pawl from the efiect of the cushioning means which prevents said pawl from fully entering the notches durin the initial movement of 'the dial, so that said pawl may then completely enter the selected notch and drive the ratchet through its impulse sending operation under the influence of a driving spring, until the dial is re turned to normal.

Referring more particularly to the drawing, the numeral l9 indicates the usual stationary number plate with which is associated the finger stop II that limits the initial rotative movement of the finger dial I 2. Said dial moves over said plate and is mounted for rotation with a hub l3 formconnected to the extremity of the pawl l5 adjacent the pivot I6. described is standard, and it will be observed that when the dial l2 and plate I4 are rotated counterclockwise as viewed in Fig. 2, the free or eflective end of the pawl l5 will ride over the teeth of the ratchet l1 and then move inwardly under the influence of the spring l8 to engage the notch of the adjacent tooth. Also in accordance with standard practice, the movement of the pawl over the teeth is such that the tooth-engaging 'face 2| of said pawl will pass slightly beyond the pawl-engaging face '22 of a tooth so that there will be a small gap between said faces which insures proper engagement of the pawl with the desired tooth at the beginning of the return movement of the finger dial. Without the provision of some cushioning means to limit the inward movement of the pawl under the action of the spring 18, the inner edge of said pawl will forcibly strike against the bottom of each notch as the pawl passes over the adjacent tooth, and this striking of the pawl against the bottom of the notch produces the undesirable clicking noise which the present invention is designed to reduce.

To accomplish this reduction in noise, there is provided a light leaf spring 23, one end of which is .fixed to a stud 24 carried by the plate l4, while adjacent its other end the spring is bowed inwardly so as to engage with the teeth of the ratchet I1 and then has its free extremity bent outwardly to provide an extension adapted for engagement with the free end of the pawl 15 which may be provided with an angular face 26 which will have flush engagement with said extension 25. The position of the extension 25 of said spring is such that it will be engaged by the end of the pawl before the latter strikes the bottom of .a notch, and the tension of said extension will be sufiicient to overcome the force of the spring 18 to the extent that said pawl will be prevented from striking the ratchet and thereby producing the above mentioned objectionable noise. Due the yieldable character of the spring '23, it will freely ride over the teeth of the ratchet during the initial rotation of the finger dial and because of its lightness no noise will be produced as it passes over said teeth.

In operation, the finger dial is first rotated counterclockwise, as viewed in Fig. 2, thereby rotating the plate 14, pawl l5 and spring 23 in a similar direction and relative to the ratchet ll. Each time that the pawl l5 rides over a tooth of the ratchet its inward movement toward the latter will be limited and cushioned by the extension 25 of said spring 23, as seen in Fig. 2, and will thus be prevented from striking directly against the bottom of the adjacent notch. When the finger of the operator strikes against the stop H at the conclusion of the counterclockwise rotation of the dial l2 and the finger is then withdrawn from the opening in said dial,

- the latter will then start its return or clockwise The construction thus far movement under the influence of the previously mentioned driving spring (not shown). The plate l4 moves with the dial and carries the cushioning spring 23 with it. At this time, said spring 23 is engaged with one of the teeth of the ratchet but the spring is of such light construction that it will have no effect upon the ratchet nor upon the pawl 15, but will rather momentarily bend or bow outwardly intermediate its ends until the ratchet starts to rotate under the driving influence of said pawl I5. As previously described, at the termination of the initial rotative movement of the finger dial, the engaging faces 2| and 22 of the pawl and ratchet tooth, respectively, are slightly spaced so that for a moment at the commencement of the return movement of the dial, the pawl 15 will be free to move relative to the ratchet until said opposed faces 2|, 22 come in contact. As a result of this slight relative movement of the pawl, it will dis- 26 from the spring extension 25 to the extent that said pawl will be permitted to fully enter the notch of the adjacent tooth from which point the pawl will positively drive the ratchetl'l in a clockwise direction so as to operate the impulse sending mechanism under the control of a governor, as is well understood in the art. I

What is claimed is: 1. In an impulse sending device, a ratchet having a plurality of teeth and intervening notches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable dial for moving said pawl in the first named direction, ,and means mounted independently of said pawl and constantly engaging said ratchet teeth and notches for limiting movement of said pawl into said notches and for cushioning the latter movement to reduce the amount of noise incident thereto.

2. In an impulse sending device, a ratchet having a plurality of teeth and interveningnotches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable dial for moving said pawl in the first named direction, and a spring mounted independently of said pawl for engagement therewith and having a free extremity in constant engagement with said teeth and notches to limit movement of said pawl into said notches.

3. In an impulse sending device, a ratchet having a plurality of teeth and intervening notches, a pawl movable in one direction over said teeth engage its surface and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable dial for moving said pawl in the first named direction, and a spring mounted independently of said pawl for engagement therewith to limit its movement into said notches, said spring engaging in said notches during said first named movement and said pawl and ratchet being so constructed and arranged that upon initiation of said other movement of the pawl the latter will move relative to said ratchet and disengage from said spring so as to fully enter one of said notches, thereby to exert said driving force upon said ratchet.

4. In an impulse sending device, a ratchet having a plurality of teeth and intervening notches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable plate for moving said pawl in the first named direction, and means mounted on said plate and positioned to engage said teeth and notches and to be engaged by said pawl during the latter movement to limit the entry of the pawl into said notches and thereby reduce the amount of noise incident to said movement.

5. In an impulse sending device, a ratchet hav ing a plurality of teeth and intervening notches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable plate for moving said pawl in the first named direction and a spring having one end secured to said plate and its other end engaged with said teeth and notches and provided with a cushioning extension engaging said pawl during said first named movement to limit entry of said pawl into said notches and thereby reduce the noise incident to said movement.

6. In an impulse sending device, a ratchet having a plurality'of teeth and intervening notches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable plate for moving said pawl in the first named direction and a spring having one end secured to said plate and its other end provided with a cushioning extension engaging said pawl during said first named movement to limit entry of said pawl into said notches and thereby reduce the noise incident to said movement, said spring extension engaging in said notches during the latter movement and said pawl being so arranged relative to said ratchet that upon initiation of said other movement it will disengage and move awai from said spring extension in a rotative direction and fully enter one of said notches.

7. In an impulse sending device, a ratchet having a plurality of teeth and intervening notches, a pawl movable in one direction over and slightly beyond each tooth so as to leave a gap between the face of said pawl and that of an adjacent tooth, said pawl being also movable in an opposite direction to exert a driving force upon said ratchet, means including a dial for moving said pawl in the first named direction, and a spring mounted independently of said pawl and engaging therewith and with said teeth and notches to limit movement of said pawl into one of said notches during said first named movement, the engagement between said spring and pawl and the gap between the latter and a tooth of said ratchet being such that when said pawl is moved in said opposite direction it will initially move relative to said tooth until said gap is closed and during said relative movement will disengage itself from said spring and fully enter the notch adjacent said tooth.

8. In an impulse sending device, a ratchet having a plurality of teeth and intervening notches, a pawl movable in one direction over said teeth and partially into said notches and in another direction to exert a driving force upon said ratchet, means including a rotatable dial for moving said pawl in the first named direction, and a spring unattached to said pawl and engaging the same only during the movement of said pawl in the first named direction to limit the movement thereof into said notches.

HAROLD T. S'I'ENHAMMER. 

